Check these first
- Touch the soil to see if it is soggy.
- Check the bottom of the pot for drainage holes.
- Gently lift the plant to inspect the roots for a foul smell.
Likely causes
Poor Drainage
Most likelyHow to tell: The soil remains soggy and the plant looks wilted despite having wet soil.
What to do: Repot the plant into a container with drainage holes using a well draining cactus mix. Trim away any black or mushy roots with clean scissors.
Overwatering
Most likelyHow to tell: The base of the stem turns brown or black and feels soft to the touch.
What to do: Stop watering immediately and let the soil dry out completely. If the rot has spread to the main stem, you may need to take cuttings to propagate a new plant.
Find out what's wrong with your crown of thorns
The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
When to worry
If the main stem is soft or mushy, the rot is advanced and the plant may be difficult to save. If only a few roots are affected, the plant can recover with better care.
Stopping it coming back
Always use a fast draining soil mix and wait until the top half of the soil is dry before you water.
Crown of Thorns: root rot? Check yours with a photo
Every plant is a little different. Take a photo of your crown of thorns and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
Get the app · Or check it from a photo now, free
Questions people ask
- Can I save a plant with mushy stems?
- If the stem is mushy, the rot has likely reached the core. Your best bet is to cut off healthy stem tips and propagate them in fresh soil.
- How often should I water to avoid rot?
- Water every 10 to 21 days, but only when the top half of the soil is dry.
More problems with Crown of Thorns
- Why is my Crown of Thorns losing its leaves?
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- Why are my Crown of Thorns leaves turning yellow?
- Why is my Crown of Thorns not blooming?
- Why is my Crown of Thorns getting so leggy?
- Why are my Crown of Thorns leaves getting brown tips?
- Why is my Crown of Thorns drooping?
- What are these spots on my Crown of Thorns?
Back to the Crown of Thorns guide
This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.

